Originally Posted by jim58
You need to read the manufacturers guidance carefully on each brand of paper. Most vinyl wallpaper will not stick to itself. If unsure, call the manufacturer of the wallpaper.
How would you do that when the "wallpaper" came from the RV factory and very likely was a pre-manufactured wall board anyway? Determining the type and manufacturer of the paper (or vinyl) is rarely practical.
If you think the existing paper is vinyl, there are two ways to deal with it:
1. Sand lightly and apply a primer paint to provide a good surface for bonding
2.Use an adhesive designed to apply over vinyl, e.g the border adhesive that Hogdriver suggested
3. Do both #1 & #2